How to accept model collection metadata, such as count in ember?

In Ember-CLI, how does one go about retrieving/storing model collection metadata?

For example, suppose I have a model 'user' with some defined attributes, and my route retrieves a collection of users with ember-data like so:

  model: function(params) {
    return this.store.findQuery('user', params);
  }
});

and the JSON response from my API looks something like this:

{ users: [{id: 1, name: 'Bob'}, {id: 2, name: 'Joe'}]}

Now, I want to add paging, which means I need a count of total users somewhere in the API response so it looks something like this:

{ user_count: 5,
users: [{id: 1, name: 'Bob'}, {id: 2, name: 'Joe'}]}

That's simple enough, but how do I access user_count from my Ember controller?

Solution

So if you are in control of the API then you can use built-in support for metadata provided by Ember Data (using DS.RESTAdapter).

If you return the following structure from your API:

{
  "users": [{
    "id": 1,
    "name": "Bob"
  }, 
  {
    "id": 1,
    "name": "Bob"
  }],
  "meta": {
    "user_count": 5
  }
}

Then you should be able to use:

var meta = this.store.metadataFor("users");

and access meta.user_count

If you are not in charge of your API you can use a serializer to format the metadata correctly. Let me know if you need more info on that.